Isolation and Identification of the Wax Esters from the

Beitrige zur Tabakforschung International · Volume 14 • No. 2 • October 1988

DOI: 10.2478/cttr-2013-0587

Isolation and Identification of the Wax Esters from the Cuticular Waxes of Green Tobacco Leaf* by

R. F. ArYentL.Ie, R. F. Severson and 0. T. Chortyk Tobacco Safety Research Unit, Agricultural Research Service, United States Department of Agriculture, Athens, Georgia, U.S.A. and

M. G. Stephenson Nematodes, Weeds and Crops Research Unit, Agricultural Research Service, United States Department of Agriculture, Tifton, Georgia, U.S.A.

SUMMARY

Recent studies in our laboratory on the cuticular chemicals of green tobacco leaf have revealed the presence of wax esters, composed of fatty acids bound to fatty alcohols. Cuticular components of young green NC 2326 tobacco leaves were removed with methylene chloride, and partitioned between hexane and SOo/o Me0H-H 20. The hexane-soluble fraction, which contained wax esters, para.ffinic hydrocarbons, and fatty alcohols, was separated by silicic acid column chromatography, and the resulting wax ester fraction was further purified by lipophilic gel chromatography. Initial analyses of the wax ester fraction by capillary gas chromatography [GC] and capillary GC I MS, on a shon fused silica [FS] SE-54 capillary column, indicated the presence of C 30 - C 52 wax esters. Application of the cold on-column injection technique and use of immobilized stationary phase, FS SE-54 capillary columns greatly improved the GC separation of the complex wax ester fraction and permitted the identification of individual wax ester isomers. Identification of wax ester isomers by GC/MS relied upon the presence of a molecular ion and ions characteristic of the acid and alcohol moieties. For the acid portion, these ions included the acid ·MW+ 1 a.m.u. and MW- 17 a.m.u. ions, while for the alcohol, they were the alcohol MW- 18 a.m.u. and

* Presented,

in pan, a' the 38dl Tobllo;o Chemisu' Research Conference, Adanta, G